code: def __mars_tokenize__(self):
      try:
          return self._key
      except AttributeError:  # pragma: no cover
          self._update_key()
          return self._key
  
imports: from typing import Dict, Tuple, Type
  from ..serialization.serializables import Serializable, StringField
  from ..serialization.serializables.core import SerializableSerializer
  from ..utils import tokenize
label_desc: Use image node_id 5 for calling the Base obj's underlying member method code with example usage: obj.__mars_tokenize__() and returns: self, self